new (B ∨ F) ∧ (B ∧ B) → (F ∧ C → (D → ((E → B ∧ C) → (E ∨ A → (A → (A → D))))))
intro
cases 0
intro
cases 3
intro
intro
intro
intro
cases 0
cases 2
cases 3
cases 11
intro
cases 0
cases 2
cases 3
cases 11
cases 20
exact 6